Sequence Of Operation; Diagnostics - Brant Radiant Heaters DX3L Series Manual

DX3L Series
This heater must be installed and serviced by trained gas installation and service
personnel only.
Do not bypass any safety features or the heater's built in safety mechanisms will be
compromised.

Sequence of Operation

Standby: The ignition module (circuit board) continually checks for internal faults, circuit integrity, and
relay contact positioning.
Starting Circuit: Upon a call for heat, the control verifies that the pressure switch(es) are in their proper
positions. The control energizes the fan. Once operational static pressure is achieved, the pressure
switch will close initiating the ignition sequence. The hot surface igniter is powered and the gas valve
opens after 45 seconds. If the flame is not sensed, the heater will attempt to re-ignite for a total of 3
trials for ignition before proceeding to soft lockout.
Running Circuit: After ignition, the flame rod monitors burner flame. If sense of flame is lost, the control
closes the gas valve within one second and a new trial sequence (identical to the starting sequence)
is initiated. If flame sense is not established within 8.5 seconds, the heater will attempt two additional
ignition sequences before proceeding to soft lockout. The control can be reset by briefly interrupting
the power source.
Shut Down: When the thermostat is satisfied, the fan will enter a two (2) minute post-purge cycle.

Diagnostics

Lockout:
The controls will automatically lockout the heater system when an external or system fault occurs. There
are two types of lockout:
Soft Lockout: The heater will attempt to light three times. In the event of a failed attempt to light (gas
pressure, valve, no flame sense etc.), the heater will enter a soft lockout period for 30
minutes and then attempt to light three more times before entering hard lockout mode.
Hard Lockout: If proof of flame is not established, a component failure occurs, or blockages are
evident, the heater will enter a hard lockout. If lockout occurs, the control can be reset by
briefly interrupting the power source. Refer to Charts 3.1 & 3.2 for a description of LED
codes.
Externally located operational indicator lights are provided to assist in troubleshooting of the heater. Refer
to pages 56-59 for additional troubleshooting.
WARNING
!
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4.0 Operation •
Sequence of Operation